Hillary Clinton refused to surrender to Barack Obama in the Democratic race for the US presidency on Tuesday or to acknowledge she had reached the end of the road in her bid for the White House.

Rather than concede the loss to Mr Obama, the New York senator told a cheering crowd she would consult supporters and party leaders to decide the future of her campaign.

Mrs Clinton praised Mr Obama and vowed to help unite the party to defeat Republican John McCain, 71, in November's election but added defiantly: "This is a long campaign and I will be making no decisions tonight."

She urged supporters to contact her campaign's Web site, saying: "I want to hear from you ... Share your thoughts with me."

Some supporters speculated Mrs Clinton was jockeying for the job of vice president on Obama's ticket. Mrs Clinton said earlier she was open to the idea, and the Obama campaign said it was keeping its options open.

A surge of support from uncommitted delegates helped give Mr Obama the 2,118 votes of convention delegates he needed to clinch the nomination and defeat Mrs Clinton, a former first lady who entered the race as a heavy favourite.

Mrs Clinton, 60, hailed Mr Obama, 46, and his supporters "for all they accomplished," saying they had run an extraordinary race for the Democratic presidential nomination. The party delegates will meet at a Denver convention in August.

"Senator Obama has inspired so many Americans to care about politics and empowered so many more to get involved," she told supporters. "And our party and our democracy is stronger and more vibrant as a result."

Despite Mr Obama's victory, Mrs Clinton planned to concentrate on winning uncommitted delegates to her side, her campaign said.

"She is still a candidate for president and is still making her case as to why she should be the nominee for president," spokesman Mo Elleithee said. "She's going to be taking the next couple of days to make her case to delegates, to unpledged delegates and superdelegates and take stock after that."

"Now that the voting's over, she has the ability to go to these remaining delegates and say look at where we stand. Look at who closed stronger."

Supporters chanted "Yes, she can" and "Yes, she will."

Patricia Williams, 45, a stay-at-home mother in the Bronx, was visibly upset by Mrs Clinton's apparent defeat.

"I've been crying all day. You see my eyes?" she said. "Whatever she does I will support her, but I wish she would take it to the convention."

New York Congresswoman Elizabeth Holtzman, who was in the crowd, said she was reminded of her own feelings after losing a close race for New York's US Senate seat in 1980. Ms Holtzman said when she lost, her campaign tried to keep going for a couple days, waiting for the counting of absentee and military ballots before conceding defeat.

"Rather than coming to grips with reality, we kept it going and it was a mistake," she said. "It would have been better to have acknowledged it."